Roku express blinking on and off constantly.

Hello, I had the same problem. Excessive ROKU blinking and slow response to my remote commands. Then getting alerts from the different channel APPs that I wasn't connected to the internet for starters. The internet WAS up and running for all the other technology in the house! I forgot my work "IT guy" training (which was "is EVERYTHING plugged in properly?") and instead forgot that went through all the unplugging of MODEM, WIFI ROUTER, waiting, getting back on and still with IFFY results. Then I replaced batteries on the ROKU remote. No change. Still blinky blinky no worky. Now, I'm not saying this wasn't part of the problem...the MODEM, ROUTER, but once I unplugged all the ROKU connections from the back of the TV to the power source and made sure ALL connections were secure for the ROKU and then plugged ROKU back in to the HDMI slot, the blinking stopped and It worked perfectly. 

Two guesses, my ROKU parts connections were loose, the ROKU was UPDATING info to my "smart TV" and I didn't have the patience to wait or a combo or part of the above. Hope this helps someone. 

SIDE BAR: I do have the ROKU HDMI extender on my TV because a couple of years ago I was having buffering problems even though the TV is plugged into the MODEM directly. The extender solved the problem.